title: Encapsulation of metalloporphyrins in a self-assembled cubic M8L6 cage: a new molecular flask for cobalt-porphyrin-catalysed radical-type reactions.
abstract: The synthesis of a new, cubic M8L6 cage is described. This new assembly was characterised by using NMR spectroscopy, DOSY, TGA, MS, and molecular modelling techniques. Interestingly, the enlarged cavity size of this new supramolecular assembly allows the selective encapsulation of tetra(4-pyridyl)metalloporphyrins (M(II)(TPyP), M = Zn, Co). The obtained encapsulated cobalt-porphyrin embedded in the cubic zinc-porphyrin assembly is the first example of a catalytically active encapsulated transition-metal complex in a cubic M8L6 cage. The substrate accessibility of this system was demonstrated through radical-trapping experiments, and its catalytic activity was demonstrated in two different radical-type transformations. The reactivity of the encapsulated Co(II)(TPyP) complex is significantly increased compared to free Co(II)(TPyP) and other cobalt-porphyrin complexes. The reactions catalysed by this system are the first examples of cobalt-porphyrin-catalysed radical-type transformations involving diazo compounds which occur inside a supramolecular cage.
authors.affiliation: Homogeneous and Supramolecular Catalysis Group, Van 't Hoff Institute for Molecular Science (HIMS), University of Amsterdam (UvA), Science Park 904, 1098 XH Amsterdam, The Netherlands.
authors.forename: Matthias
authors.initials: M
authors.lastname: Otte
authors.forename: Petrus F
authors.initials: PF
authors.lastname: Kuijpers
authors.forename: Oliver
authors.initials: O
authors.lastname: Troeppner
authors.forename: Ivana
authors.initials: I
authors.lastname: Ivanović-Burmazović
authors.forename: Joost N H
authors.initials: JN
authors.lastname: Reek
authors.forename: Bas
authors.initials: B
authors.lastname: de Bruin
mesh_terms: D001391:Azo Compounds / Q000737:chemistry; D002384:Catalysis; D003035:Cobalt / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008665:Metalloporphyrins / Q000737:chemistry*; D008956:Models, Chemical; D015394:Molecular Structure; D015032:Zinc / Q000737:chemistry*
chemical_list: D001391:Azo Compounds; D008665:Metalloporphyrins; D003035:Cobalt; D015032:Zinc
keywords: cubic cages; homogeneous catalysis; host-guest chemistry; radical chemistry; self-assembly